1 package cn.itcast.p10.map.test;
 2 
 3 import java.util.HashMap;
 4 import java.util.Map;
 5 
 6 public class MapTest2 {
 7 
 8     public static void main(String[] args) {
 9         // TODO Auto-generated method stub
10         /*
11          * Map在有映射关系时，可以优先考虑。
12          * 
13          * 在查表法中的应用较为多见。
14          */
15         String week = getWeek(1);
16         System.out.println(week);
17         
18         System.out.println(getWeekByMap(week));
19     }
20     
21     public static String getWeekByMap(String week) {
22         Map<String,String> map = new HashMap<String,String>();
23         
24         map.put("星期一", "Mon");
25         map.put("星期二", "Tus");
26         map.put("星期三", "Wes");
27         map.put("星期日", "Sun");
28         map.put("星期天", "Sun");
29         
30         //map.put("预热班", "张三");
31         //map.put("预热班", "李四");键唯一会覆盖
32         //map.put("预热班", "王五");
33                   //以上可以map.put("预热班",Set<Student>);可以把value放在集合里
34         return map.get(week);
35         
36         
37     }
38     
39     public static String getWeek(int week) {
40         
41         if (week<1 || week>7) {
42             throw new RuntimeException("没有对应的星期，请您重新输出");
43         }
44         String[] weeks = {"","星期一","星期二"};
45         
46         return weeks[week];
47     }
48 
49 }

MapTest2